Two fragments overlaps due to addBackStack

Question

From my main activity, pressing Settings button opens an AppCompatActivity with FrameLayout as the container for the fragments. In OnCreate method, I'm adding the fragment which is a PreferenceScreen container.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.settings);

    Toolbar toolbar = (Toolbar) findViewById(R.id.custom_toolbar);
    setSupportActionBar(toolbar);

    ActionBar ab = getSupportActionBar();
    if (ab != null) {
        ab.setDisplayHomeAsUpEnabled(true);
        ab.setTitle("Settings");
    }


    FragmentManager fragmentManager = getSupportFragmentManager();
    Fragment fragment = null;
    if (savedInstanceState == null) {
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

        fragment = SettingsFragment.newInstance(null);
        fragmentTransaction.add(R.id.fragment_container, fragment);

        fragmentTransaction.commit();
    }
}

Pressing again another button called Options, opens replaces fragment with Options fragment adding the current class to backstack.

@Override
public boolean onPreferenceStartScreen(PreferenceFragmentCompat caller, PreferenceScreen pref) {

    FragmentManager manager = getSupportFragmentManager();

    SettingsSubscreenFragment fragment = null;
    Bundle args = new Bundle();

    switch (pref.getKey()) {
        case "pref_key_rejection_options":
            getSupportActionBar().setTitle("Rejection Options");
            fragment = SettingsSubscreenFragment.newInstance("Options");

            break;
    }

    args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, pref.getKey());

    if (fragment != null) {
        fragment.setArguments(args);
    }

    FragmentTransaction ft = manager.beginTransaction();
    ft.replace(R.id.fragment_container, fragment, pref.getKey());
    ft.addToBackStack(null);
    ft.commit();

    return true;
}

When I press the Up Button, I'm just replacing the Options fragment to the first fragment, Settings, which does not pop the back stack.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            getSupportActionBar().setTitle("Settings");

            FragmentManager fragmentManager;
            FragmentTransaction ft;
            Fragment fragment = null;

            if (getSupportFragmentManager().findFragmentByTag("pref_key_options") != null) {
                fragmentManager = getSupportFragmentManager();
                ft = fragmentManager.beginTransaction();                 

                fragment = SettingsFragment.newInstance(null);


                ft.replace(R.id.fragment_container, fragment);
                ft.commit();
                fragmentManager.getFragments().clear();


                return true;
            } else {
                return super.onOptionsItemSelected(item);
            }

    }
    return super.onOptionsItemSelected(item);
}

So, opening the Options fragment again will add another to back stack and onBackPress, it only pops the topmost and leaves its shadow overlapping the other one registered in back stack.

@Override
public void onBackPressed() {
    int backStackCount = getSupportFragmentManager().getBackStackEntryCount();

    if (backStackCount >= 1) {
        getSupportActionBar().setTitle("Settings");
        getSupportFragmentManager().popBackStack();
    } else {
        super.onBackPressed();
    }
}

The almost the same situation is like from here, third picture of the question, but I can't make it work with their suggestions.

What am I doing wrong and what I can do to make this work? Thanks a lot.

Answer 1

Check FragmentTransaction , SettingsSubscreenFragment and SettingsFragmentare extending android.support.v4.app.Fragment . If not , try

class YourFragments extends android.support.v4.app.Fragment 

in your fragment classes.